Researchers in Brazil have confirmed the presence of a new bacterial disease in corn in the state of Parana in southern Brazil. The Agronomic Institute of Parana (Iapar) recently sent out an alert to farmers in the state indicating the presence of the new disease.

The new disease is bacterial leaf streak (Xanthomonas vasicola pv.), which is a foliar disease that causes long cloratic streaks on corn leaves. In a severe infestation, as much as 70% of the leaf tissue may be impacted. There are no studies indicating the amount of yield reduction that may be caused by the disease, but researchers estimate that if 40% of the leaf tissue is destroyed thus reducing the photosynthetic activity of the plant, the potential yield losses could be as high as 50%.

The disease was first discovered in the United States in 2016 in the state of Colorado and then in Argentina in 2017. Previously, it had been identified in South Africa as far back as 1949.

Scientists in the state of Parana have identified 30 corn hybrids that are susceptible to the disease. Since it is a bacterial disease, there are no current treatments other than selecting hybrids that are not susceptible. Scientists have not indicated how widespread the disease is within the state or if it has spread to other regions of Brazil.

Since the disease was not previously identified in Brazil, it is possible that more than 30 corn hybrids may be susceptible to the disease. It remains to be seen if this disease will be an impediment to corn production in the state or if it was just the local environmental conditions allowed the disease to flourish this past growing season.